Pollen ID in Honey
Oh how I love this time of year- the sun is shining and the honey is flowing In the two months since we sent scales out back in April, a lot of beekeepers saw their hives put on a substantial amount of gain, with some hives doubling in weight, gains of more than 50 lbs and some over 100 lbs! Now originally I wanted to include a botany component to this project, asking beekeepers to survey the available forage throughout the season within 1-2 miles of their apiary. Realizing that this might be asking too much and still having to work out other elements of the project, I decided to drop this component. However, when Neil Roberson, a local Halifax beekeeper and owner of Enfield Bee Farm, contacted me a few weeks ago about Bayer’s capacity to analyze honey, I realized we could actually gain some insight into the available forage based on the pollen found in honey!
Neil was interested in looking at pollen after seeing a big difference in the honey he extracted this year compared to last year and years past. Here is a picture Neil sent me of his honey from 2016 in the left jar, and honey from this year shown in the two jars on the right…so a pretty obvious difference. This spring, several people noticed blackberry blooming before tulip poplar so it is possible this had something to do with the difference in color. But to be sure, we had to take a closer look under the microscope!
For our honey bee field studies, we have relied on the expertise of palynolgists Vaugn Bryant at Texas A&M and Sophie Warny at LSU. Vaughn was recently recognized for his outstanding accomplishments throughout his career, which you can read about in Bee Culture. An excerpt from one of Vaugn and Sophie’s analyses for a study in NC is shown here with identifications listed below. If you want to look through 64 pages of pollen pictures you can find the attached report here. And if you are really interested in honey testing, check out the honey board’s website for labs equipped to analyze pollen (spoiler alert, there are only two!)
Now to satisfy our own curiosities and for the sake of learning, Neil came and visited the Bee Care Center and brought his honey to take a stab at pollen ID’s. We first diluted and mixed the honey with water before we placed the samples into the centrifuge at 4000 RPM for 5 minutes. Alternatively, you can also mix the honey with warm water and let it sit out for several days but with either method, a pollen pellet should form at the bottom of the tube. Here are pellets from the 5 monofloral nectar sources we looked at:
Careful not to disturb the pollen pellet, we poured off the honey water and transferred the pollen to a microscope slide and started looking at it at 400X magnification. Now these pictures will look different from the pollen report since we did not use acetolysis to clean up the samples but here’s what we saw for out monofloral honeys:
The national honey board requires beekeepers to have the honey analyzed if they want to label their honey as a monofloral honey. According to their standards, 50% of the pollen must be attributed to a single floral source in order to be labeled as a single source. When I first heard 50% I thought that was quite low but after looking at the amount of different pollens in these monofloral honeys, I understand why! There are also so many similar shapes and sizes that it is incredibly difficult to differentiate between them to successfully identify it. And not only do you have to figure out what plant a specific pollen grain came from, you also have to figure out the relative quantity! Nectar producing plants offer different amounts of pollen, resulting in an overrepresentation of certain pollens that might not be related to where they got the most nectar from, and vice versa. Some samples might have a few grains of one type of pollen but because that plant offers very little pollen per nectar visit, even though there are few grains of it, it is actually the dominant source of nectar for them! So to actually figure out which plants are your major contributors, you have to use pollen coefficients, determined by Vaugn Bryant and Gretchen Jones https://www.honeyacres.com/images/1-r-value.pdf.
Now back to Neil’s mysterious honey:
I was naiively hoping to be able to provide definitive answers and identifications to Neil but it was abundantly clear that was not possible. So we couldn’t provide the simple answer he might have originally been hoping for, but I think he was at least able to walk away with a new appreciation for pollen!
So after we looked at Neil’s pollen, we decided to look at honey from some of our staff’s personal hives:
You might notice that Kim’s honey is red! Her hive was involved with a side project where we fed a hive sugar water with red food dye in the fall..looks like there was plenty of it left over in the spring! We are repeating that study this next month so stay tuned for another special feature on that!
So after looking at all this pollen with Neil and the bee care center staff, I was still eager to look at more samples, at which point I contacted Tim Huffman who brought over 5 more samples from 5 different areas taken this year!
There were some grains that seemed to be recurring culprits that I believe to be in the clover family and blackberry family but I am not too confident in those identifications! But with these pictures, maybe some can take a stab at studying these pollen grains!
All in all, this was a very enlightening experience that I'm glad Neil and Tim could be a part of!